NEW YORK (Reuters Health) - Coffee and tea lovers may have
a slightly reduced risk of developing kidney cancer, research
hints.

The findings, based on an analysis of 13 previous studies,
suggest that coffee and tea may be protective against kidney
cancer, while milk, soda and juice seem to have no effect one
way or the other.

Across the studies, people who drank three or more cups of
coffee a day were 16 percent less likely to develop kidney
cancer than those who averaged less than a cup per day. And
those who sipped just one 8-ounce cup of tea each day had a 15
percent lower risk of the disease than non-drinkers.

The findings appear in the International Journal of Cancer.

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While the study cannot show that coffee or tea directly
lower kidney cancer risk, there are reasons why the beverages
could be beneficial, according to the researchers, led by Dr.
Jung Eun Lee of Harvard Medical School in Boston.

For example, they explain, coffee and tea may increase the
body's sensitivity to the blood-sugar-regulating hormone
insulin, and researchers suspect that insulin levels over time
may affect kidney cancer risk.

Coffee and tea also contain antioxidant compounds that may
help protect cells in the kidney from cancer-promoting damage,
the researchers point out.

For their study, the investigators combined the results of
13 long-term studies that included a total of 530,469 women and
244,483 men. Each study collected information on participants'
diets at the outset and then followed them for seven to 20
years.

Coffee and tea consumption were linked to a lower risk of
kidney cancer even when the researchers accounted for a number
of factors known to affect people's risk of the disease -- such
as obesity, smoking and high blood pressure.

"Our results suggest that coffee and tea consumption may be
associated with a modestly lower risk of (kidney) cancer,
whereas intakes of milk, juice and soda were not associated
with risk," Lee's team writes.

They say more studies are needed to understand why coffee
and tea might be protective against the disease.